Machine foe



OLIVER FFCE,

ALLEN, OF NORWICH, CONNECTICUT.

MACHINE FOR DREDGING OR EXCAVATING.

Specification of Letters Patent No. 4,020, dated May 1, 1845.

T 0 all whom z' may concern Be it known that I, OLIVER ALLEN, ofNorwich, in the State of Connecticut, have invented a new and usefulimprovement in Machinery for Dredging or Excavating Earth for thePurpose of Deepening Rivers, Harbors, &c.; andI do hereby declare thatthe nature of my invention and the manner in which the same is to beperformed are particularly described and ascertained in and by thefollowing statement thereof, reference being had to the drawings accompanying and making part of the same and to the figures and lettersmarked thereonthat is to say, Figure l of the drawings aforesaidrepresents a top or plan view of my improved dredging-machine. Fig. 2 isa side elevation of the same, and Fig. 3 an elevation o-f its front end.

A, Figs. l, 2, denotes' a vessel or sco'w, having a semicircular orother proper shaped bow and a circular railway B, arranged upon itsdeckat the bow, as seen in the drawings. At t-he center of the railwayis a capstan C, and over the capstan and railway a long crane D, whichextends beyond the bow and rearward over the railway as seen in l, 2.

The crane turns around horizontally upon a central vertical shaft,carried downward through the capstan, and it has a grooved wheel E fixedwithin it, so as to bear and move upon the railway; the said wheel beingarranged at the foot of a long mast F, raised vertically upon the craneas Seen in Figs. 2, 3; and being composed of two planks a, a, united attheir upper and lower ends by horizontal cross pieces b, 0,'. each ofthe said planks being bolted or otherwise properly secured to the outerside of the crane.

The crane may be said to be composed of a long beam or lever CZ, unitedor connected with the mast before mentioned by a horizontal beam e, andinclined struts f, f, the beams CZ and e, having a space g, formedvertically through them so as to receive the pole 7i., of theexcavating` bucket z', and permit of the movement thereof to take placewithin it.

The pole of the bucket or scoop, is arranged in fro-nt of the mast andhas its turning fulcrum Z disposed between the struts f f, in theposition as seen in the drawings.

A long lever or arm G, (composed of two planks la, 7c, connectedtogether at their front ends by an intervening` piece of wood Z) isapplied to the crane in such manner, as to turn vertically upon afulcrum or bearing (at m), extending from the struts. The rear end ofeach plank 7a, abuts, when the lever is in its lowest position, againsta stop n. The excavating bucket is suspended by two lines or chains 0,0, each of which is attached to it in rear of the pole It, and extendsupward and is attached to, and winds upon, a grooved pulley or barrelZ2, placed upon a horizontal shaft g, at the top of the mast.

The bucket and its pole are counterbalanced by a weight 1", attached toa chain or rope s, which depends from and winds about a grooved pulleyor barrel t, placed by thev side of the grooved pulley 79, upon the sameshaft with it. The bail u, of the excavating bucket, has a line or chainfv, extending from it and through the end of the arm G (that is, betweentwo grooved pulleys or sheaves w, fw, arranged therein), thence upwardthrough the front end of the crane and over a sheave m, thence through aleading block y, arranged upon the top of the crane, thence along thetop of the crane, toward and through its rear end, and over a slieave atherein, and thence is carried to and wound upon the capstan C.

The above particular arrangement of the crane, capstan, and chain whichwinds around the latter, and lifts the excavating bucket, is one of verygreat convenience and importance, inasmuch, as by it, I am enabled toturn the crane around throughout an entire circle, without twisting thechain in the slightest degree. The carrying the chain through the afterpart of the crane, and thence forward and upon the capstan soconcentrates the forces in action upon the crane as to bind its partstogether, and thereby cause the strains upon it to act in suchdirections as to insure or promote its stability. It also presents thechain to the capstan, at a` proper distance to enable it to freely windthereon, without any injurious tendency of riding or overlapping of itscoils. The twistino of a chain is a great point to be guarded against,as, when such takes place, even to a very small extent, there is greatliability of fracture or rupture of it.

Steam, or horse, or other suitable power, is to be applied to thecapstan, in such manner as may be required to operate it, so as Cil towind up the chain or line which actuates the excavating bucket. Thecapstan should have a mechanical arrangement, by which it may be readilydisconnected from the power which turns it, so as to permit theexcavating bucket to descend to the depth required, after being drawn upand its contents discharged. It should also have a friction brakeapplied to it, by which the descent of the bucket may be regulated.

The maintenance of the crane in any required position, and thepreventionof its slipping upon the circular railway is a matter ofconsiderable importance. To effect this, a series, or beveled wheel ofvertical cogs, may be applied to either the exterior or interior side ofthe circular railway, and the wheel of the crane, which rests and movesupon the railway, may have a beveled pinion arranged by the side of iton its axis, and so as to engage with the aforesaid horizontal beveledwheel. The friction brake which acts upon the railway wheel of thecrane, will thus be enabled to act with the requisite certainty. Or,instead of the above, any other suitable contrivance may be adopted. Thecrane should also have an apparatus or mechanical contrivance adapted toit, and of such character as will enable an attendant to connect theturning shaft of the crane, or the crane itself, with the power by whichthe capst-an is operated, or with the capstan; the same being for thepurpose of moving the crane upon the railway to the point required, tobring the excavating bucket over the barge or scow, into which its loadis to be deposited, or to bring the said bucket over any spot where itmay be desirable to discharge its contents. There should also be somesuitable mechanism, connected to the crane, for reversing its mo tions,or bringing it back over the spot where the excavation is beingperformed. The shaft of the grooved pulley 79 should have a frictionbr-ake or apparatus applied to it (to be actuated by a lever or othersuitable contrivance, within reach of the attendant, who stands upon aplatform K), in order to regulate the descent of the excavating bucket.There may also be a friction brake or any other proper mechanicalcontrivance applied to the crane wheel (which rests and moves upon therailway 13,) and railway, for the purpose of arresting or regulating themotion of the crane upon the railway, as may be required.

As the bucket is drawn forward in the act of excavating, it is to beforced downward by a snubbing line attached to its pole, and operated inthe usual manner, or any other suitable mechanical contrivance may beadapted to it, to effect the same end. The adjustable arm G, serves tobring down the line or direction of draft upon the excavating bucket,thereby causing the same to scrape up the earth with certainty and ease.It rises and falls with the bucket, and may, if desired, becounterbalanced.

rIhe above described peculiar arrangement of the several parts, rendersthe dredge almost, if not entirely, applicable to every kind ofexcavation beneath the waters surface. The open mast, the adjustablearm, and particular crane admit of a bucket pole of great length beingused within the unobstructed space g. rear part of the crane beyond thepoint of bearing upon the circular railway, is very advantageous;inasmuch as it presents an opportunity to apply a weight thereon inorder to counterbalancc the crane and trim the dredge.

Having thus described my invention. I shall claim, my improvement indredging machinery; the same consisting in the arrangement of the mastdirectly upon and so as to be supported by the movable crane, in suchmanner as to be moved by, and with the crane, whenever the latter isturned horizontally toward the right or left, instead of making the saidmast a fixture to the deck of the vessel or dredge, as heretofore.

I claim- The above described peculiar arrangement, with respect to eachother, of the capstan and crane; and, in combination therewith, that ofthe chain which elevates the excavating bucket, the latter differingfrom other arrangements thereof in being carried through the rear orafter end of the crane, in the manner and for the purpose as hereinbefore specified.

In testimony whereof, I have hereto set my signature, this third day ofMarch 1845.

OLIVER ALLEN.

Witnesses:

PHiLo M. JUDsoN, EDWARD Y. THOMAS.

The extension of the-

